Verify that a page is usable by people with color blindness

To check that a webpage is usable by people with color blindness, in the Rendering tool, use the Emulate vision deficiencies dropdown list.

On the accessibility-testing demo webpage, the different donation states use color as the only means of differentiation:

  • Green means a high amount of donations have been received.
  • Yellow means a medium amount of donations have been received.
  • Red means a low amount of donations have been received.

But you can't expect all of your users to experience these colors as intended. By using the Emulate vision deficiencies feature of the Rendering tool, you can find out that this design isn't good enough, by simulating how people with different vision would perceive your design.

To check whether a webpage is usable by people with color blindness:

  1. Open the accessibility-testing demo webpage in a new window or tab.

  2. Right-click anywhere in the webpage and then select Inspect. Or, press F12. DevTools opens next to the webpage.

  3. Press Esc to open the Drawer at the bottom of DevTools. Click the + icon at the top of the Drawer to see the list of tools, and then select Rendering.

  4. In the Emulate vision deficiencies dropdown list, select Protanopia. Protanopia is reduced sensitivity to red light, making it hard to differentiate green, red, and yellow.

    Showing the document as someone with protanopia would see it.

  5. In the Rendering tool, below Emulate vision deficiencies, select No emulation to remove the simulation.

See also